Mervi was the scientific coordinator of the experiments that successfully proved the use of waves tuned to the third harmonic ion cyclotron resonance of deuterium (D) to heat the plasma. Various diagnostics including neutron detectors and neutral particle analysers confirmed the presence of energetic D ions accelerated by resonant wave-particle interaction.

The paper entitled “Modelling of JET hybrid plasmas with emphasis on performance of combined ICRF and NBI heating” has been published by Nuclear Fusion. It advances our understanding of the optimisation of fusion performance of the recent Joint European Torus (JET) hybrid plasmas. The hybrid scenario is an advanced regime of tokamak plasma operation expected to be applied in ITER. It is characterized by a low plasma current Ip which allows operation at a high normalised beta as well as a safety factor at the plasma centre greater than 1 which is beneficial from the plasma stability point of view.

The paper focuses on the impact of neutral beam injection (NBI) and specially ion cyclotron resonance frequency (ICRF) heating on the neutron production rate. The main scheme studied is minority hydrogen (H) in a deuterium (D) plasma with D beams. The modelling takes into account the synergy between ICRF and NBI heating through the second harmonic cyclotron resonance of D beam ions which allows us to assess its impact on the neutron rate RNT. Apart from the D scenario, the deuterium-tritium (DT) scenario is also assessed through an extrapolation of D high-performance hybrid discharges. These results are relevant for the forthcoming DTE2 campaign at JET where one of the goals is to achieve the highest possible fusion performance for a duration of more than 5 s.

One of the key requirements to achieve steady-state power production in a fusion reactor based on the so-called tokamak configuration is to generate non-inductive toroidal plasma current in an efficient way. A recent paper published in Physical Review Letters entitled “Observation of Efficient Lower Hybrid Current Drive at High Density in Diverted Plasmas on the Alcator C-Mod Tokamak” reports on the use of lower hybrid current drive (LHCD) as an efficient mean to obtain non-inductive plasma current at high plasma densities in a diverted tokamak configuration such as Alcator C-Mod.

Dr John Wright, Principal Scientist at Plasma Science and Fusion Center at MIT (USA) visited the BSC fusion group for two weeks in March, funded by BSC Severo Ochoa incoming mobility funding. The objective of his visit was to install the All-Orders Spectral Algorithm (AORSA) code at MareNostrum.

Whether the nuclear fusion approach is based upon magnetically confined plasmas or inertial confinement, the underlying idea is the same, to fuse nuclei made up of protons and neutrons into a more massive nucleus. But what if there exists other physical mechanisms?

A recent paper published in Nature by Marek Karliner and Jonathan L. Rosner describes the fusion reaction at a quark-level by the double charmed baryon discovered at CERN, Geneva. CERN hosts the Large Hadron Collider (LHC) which is the world’s largest and most powerful particle collider which intends to discover the fundamental structure of the universe.

Dr. Mervi Mantsinen and Dani Gallart at the entrance hall of JET facilities at Culham, UK.

The General Planning Meeting (GPM) of the Medium Sized Tokamaks (MST1) was organized this year at at the JET facilities, Culham, UK. The meeting started with an overview of the present status of AUG (Garching, Germany) and TCV (Lausanne, Switzerland) tokamaks. They were followed by a presentation on MAST-U(Culham, UK) which will be back in operation next year with the new and exciting Super-X divertor. It will be able to drastically reduce the divertor heat load from particles leaving the plasma.